Punch



p 9, 1969 I M. E. BLAIS 3,465,634

PUNCH Filed Feb. 20. 1967 Ill-In I!!! gm; IQ] 16a 41 L2 FIE 1 41 IIyVENTOR. AMue/cz- E 844/6" r a/d United States Patent US. Cl. 83-695 3 Claims ABSTRACT OF THE DISCLOSURE A punch adapted for punching thin flexible materials, including a punch member and a die arranged in axially aligned relationship, means are provided for shifting the punch into engagement with the die for cutting therebetween, the punch surface including a punching face with a plurality of non-die engaging portions whereby areas of attachment are provided between the punched area and the work. As a further feature, the punch is provided with a stripper arranged to be shifted into the area defined by the punch face to break away the attachment areas and remove the punched slug from the work, the stripper member having a pin means which is arranged to pierce the surface of the work prior to the time of engagement between the stripper and the slug.

A punch mechanism for forming openings in substantially thin sheet materials which punch includes a first punching and forming mechanism brought into registration with the material to be punched and forming in cooperation with a mating die an opening therethrough except for select places about the opening wherein the punching is not accomplished and the material within the punched area and the remainder of the material remains joined at a plurality of positions. This punch mechanism is then followed by a knock-out mechanism which is received into the punch area and drives the punched area outwardly therefrom tearing the areas which have been previously joined to the main portion of the material. This punching and knockout sequence is controlled by providing biasing means of different strengths such that the punch will be actuated and the punching operation completed before the knock-out process is initiated.

In punching substantially thin materials, a problem exists due to the ability of the material to deform about the punch member. As a result, the openings to be punched often are not clearly defined and the material often leaves the punch area carrying along the supposedly punched slug.

The device provided by applicant incorporates a unique punching face having a plurality of non-punch areas spaced thereon, which areas will hold the punched slug onto the carrying material and includes a slug stripper member sequentially driven into the slug to tear the minimal joined sections of the carrier material from the punched slug and carry the punch well away from the carrier material. In other words, the device actually provides a unit which will hold a punched slug in proper stripper position such that the stripper may exert its knock-out force entirely thereagainst, and as such, will complete the punching operation by tearing the partial attachment segments.

The operation of applicants punch is sequential in that the primary punching member is initially engaged with the material to be cut to perforate at least a major portion thereof leaving minimal attaching sections between the punched slug and the carrier material and thereafter, on a continuing stroke of the main punch carrier, to move the stripper into contact with the now defined slug and strip the same from the carrier material.

This operation is entirely sequential due to an arrangement of the biasing means between the longitudinal or axial drive member and the punch itself.

It is therefore an object of applicants invention to provide an improved punch member which will substantially define a punch area and will hold the punched slug therein for a subsequent stripping and knock-out action delivered to the defined slug.

It is a further object of applicants invention to provide a unique sequential punching operation wherein a first major punch member substantially perforates and defines the slugs to be punched and thereafter a stripper member is engaged with the slugs to be punched for stripping from the carrier material. The operations occurring in a sequential arrangement on a single stroke of the drive or tool member.

It is still a further object of applicants invention to provide a punch and stripper member which will substantially remove a punched slug away from a carrier film once it has been cut from the film so that it will not be carried along thereby.

These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawing, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a side elevation illustrating a punch embodying the concept of applicants invention in proper punching position on a supporting frame.

FIGURE 2 is a vertical section taken substantially along line 22 of FIGURE 1.

FIGURE 3 is a perspective view of the punch element particularly illustrating the non-punching areas thereof.

FIGURE 4 is a view similar to FIGURE 3 illustrating the stripper mechanism in knock-out position with respect to the punch face.

In accordance with the accompanying drawings, the punch embodying the concept of applicants invention, is generally designated 10 and includes a frame assembly 11, a lower die assembly 12, and means for driving the punch 13, which means may be a simple reciprocating shaft member having means for connecting the shaft member to the punch proper. The support frame 11, in the form shown, consists of a punch guide portion 14 extending outwardly from a vertical support member 15 and spaced above a lower die retaining section 16. An additional shaft guide member 17 may be provided in upwardly spaced relationship from the punch guide member 14, as illustrated in FIGURE 1. A plurality of aligned apertures 14a, 16a, 17a are provided respectively in each of the supporting and guiding elements 14, 16, 17 to provide an axial arrangement for positioning the respective portions of the punch system therein.

The punching section of thi device 10 is generally designated 20, and includes in the form shown, a substantially cylindrical punch member 21 arranged for vertical reciprocation in guide passage 14a and includes, at the lower end thereof, a punch face 22 and at the upper end thereof, a stop shoulder 23. This cylindrical punch member 21 is substantially hollow over a major portion thereof to provide a cavity 21a therein for housing a stripper member generally designated 30, and likewise is provided with a passage 2111 on the upper end thereof adjacent the shoulder portion 23 to permit attachment thereof to the driving means 13.

One method which may be utilized to attach the punch 10 to the driving means 13 is to provide a pair of bifurcations 31-31 at the uppermost end of the stripper member 30 and provide the driving means 13 with a downwardly extending leg 13a to be received between the bifurcations 31-31 with a pin member 32 providing the connection therebetween.

In the form shown, a first spring member 22 is provided between the aforementioned upper shoulder 23 and the uppermost surface 14b of the punch guide support 14. This spring 22 is compressive in nature and tends to return the punch cylinder 21 into an uppermost position, as illustrated in FIGURES 1 and 2.

In order to provide connection between the punch member 21 and the stripper 30, a pair of inwardly extending pins 24-24 are provided radially through the aforementioned shoulder portion 23 to extend into the cavity 21a of the cylinder 21 such that an uppermost shoulder 30a of the stripper will normally abut thereagainst on its upward stroke, which abutment will serve to not only aid the spring 22 in returning the punch cylinder 21 to its upward position, but will likewise capture the stripper 30 within the cavity 21a.

The punch face 22 of the punch 21 is, in the form shown, angularly arranged with respect to the longitudinal axis of the cylinder 21 to provide an upwardly beveled face 25 thereon. This is the actual punching face of the punch and will, when in operation, mate with the lower die section 12 to cut the material M therebetween. The particular shape of this die face 25 is not highly critical although the applicant has found that an angular arrangement with respect to the axis of the cylinder of approximately 40 degrees is highly efficient and provides proper cutting. It should be obvious that this particular plunger face 25 could be of many different shapes depending upon the particular opening being cut into the material M and applicant does not wish to limit himself to a particular design for the plunger face except as hereinafter follows.

The important aspect of the plunger face 25 is the provision of a plurality of grooves 26 arranged thereon and extending therein. These grooves 26 are cut into the face 25 of the punch such that when the punch face 25 mates with the corresponding die, no material will be cut in these areas and rather, the slug being punched will be retained by certain uncut sections spaced therearound to hold the same in substantially the same planar relationship with the material as before punching of the material. These sections of attachment are substantially small but do afford the strength to retain the punched area in position below the punch to afford striking thereby by the knock-out and stripper member 30. It should be obvious that to properly hold such a knock-out section for stripping that at least three such sections of non-perforation 26 should be provided about the punch face 25.

In order to afford the striker or stripper member 30 the action to strip the low selectively held slug S from the material M an aperture 22a is provided substantially centrally and axially of the punch face 25 such that the stripper 30 is free to reciprocate therein. As illustrated in FIG- URE 2, a needle point 33 is provided axially of the stripper 30 and is held herein by a set-screw or the like 33a with the piercing point of the needle 33 extending outwardly from the end of the stripper 30. It should also be observed that, as illustrated in FIGURE 2, in the retracted position, the pin member 33 is well behind the foremost end of the punch face 25. A second spring member 34 is contained within cavity 21a and abuts at one end with the outwardly extending shoulder 30a of stripper 30 and at the other end with the cavity surface 21b surrounding the aperture 22a of the punch 21. This spring member 34 is of substantially higher compressive force than the aforementioned spring member 22 such that in operation, when a longitudinal axial force is provided by the driving means 13, the punch member 21 will compress spring 22 to be driven into mating relationship with the lower die 12 affording the first cut into the material without shifting the stripper 30 relative to the punch cylinder 21. After the punch member 21 has been driven down to mate with the die and cut the material M, the continued axial force of the driving means 13 will force the stripper member 30 downwardly into the new selectively .4 held slug S and included in this motion the pin member 33 will pierce the film substantially centrally thereof and the continued downward force will break the selective attachment areas. The pin member 33 serves the function of locating the slug S properly with respect to the stripper 30 and it should be obvious that when cutting particularly thin materials, this location is necessary as otherwise it could be possible that one of the selectively held areas would break before the other of such areas therefore permitting the slug to bend about the other still connected areas and prevent the tearing thereof from the material M.

The lower die section 12 includes a substantially cylindrical unit 40 received into the die guide aperture 16a and the die support 16, and includes a lower flange 41 extending outwardly from the cylindrical portion 40 such that the die may be properly held into the guide 16 and properly positioned with respect to the surface of the support 16b over which the material M will travel. The die 40 is provided with a longitudinal passage 42 therethrough, which passage terminates in the actual die passage 43 formed upwardly therein, which die passage 43 terminates at its upper surface 40a which surface corresponds to the top-most surface of the die support 16 and which is the mating surface for punch 10.

As illustrated in FIGURE 2, the stripper member 30 is designed to be received into passage 43 such that it will push the defined slug S entirely therethrough and into the substantially larger cavity 42 therebelow. This pushing of the slug S is important in that it is necessary to completely remove the slug S from the material being cut to prevent the slug S from being carried therealong.

The operation of the punch should be substantially selfexplanatory, but a short description is given hereinafter. As the drive member 13 is driven downwardly, the fact that spring member 22 is of less compressive strength than the internal spring of stripper 34, will permit the spring 34 to actually drive against the lower internal portion 21b of cavity 21a and drive the punch 21 downwardly into mating cutting position with the die 40, and more particularly with the die passage 43 in the die 40. This downward function will, as previously stated, cut a slug in the material, which slug is retained onto the material through a plurality of substantially small connective links, being the links in the areas of non-cutting 26 of the punch face 25. After the punch face 25 has been driven into cutting relation with the die 40, the continued downward motion of the drive means 13 will force the stripper member 30 downwardly through passage 22a where the needle point 33 will be driven into the partially held slug S and continued downward motion will rend the still attached portions of the slug S from the material M and will subsequently force the slug S to be delivered through passage 43 into the larger area 42 completely away from the carried material M. Retraction of the drive means 13 and removal of the downward force from the drive means 13 will, of course, permit the compressive springs 22 and 34 to force the stripper 30 and punch element 21 upwardly into proper position well above the material M to allow the material to be moved therepast to the next punch location.

Although illustrated in circular form, it should be obvious that this same concept could be utilized in any particular shape, and of course, in more complicated shapes, it may be necessary to properly locate the non-cutting areas of the punch face about the slug.

It should be obvious that applicant has provided a new and unique punch mechanism for partially retaining slugs from punch areas until a stripper member moved in sequential relationship to the punch is available to rend the slug from the material, thereby preventing the slug from folding under or being carried along with the material after supposed cutting.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of the invention as set forth in the appended claims.

What is claimed is:

1. A punch adapted for punching thin materials, including:

(a) a punch member;

(b) a die arranged in aligned relation to said punch member;

(c) means for shifting said punch into engagement with said die for cutting therebetween;

((1) said punch including a punching face having a plurality of non-die engaging portions thereon whereby areas of attachment are provided between the punched area and the material; and

(e) a stripper member arranged and constructed to be shifted into the area defined by said punch face to break the attachment areas and remove the punched area from the material, said stripper being arranged and constructed to be shifted by said punching shifting means; and

(f) differential biasing means connecting said punch member and said stripper member to said punch shifting means permitting said punch member to perform the punching operation before actuating the stripper member.

2. The structure as set forth in claim 1 being particularly characterized in that said stripper member is provided with a forward face having pin means disposed therealong, said pin means being arranged to pierce the surface of said thin material prior to the time of engagement between said forward surface and said pin material.

3. The structure as set forth in claim 1 and said biasing means including a pair of spring members having different compressive strength respectively operatively associated with said punch and stripper members.

References Cited UNITED STATES PATENTS 2,501,682 3/1950 Kuchman 83-428 2,789,640 4/1957 Belden 22596 XR LEONIDAS VLACHOS, Primary Examiner US. Cl. X.R. 

